> PPC arch compiles with -fno-builtin. Why is this? It seems sub-optimal> and non-uniform, leading to little platform discrepancies like this...

Have you tried it without -fno-builtin? If you do, gcc grumbles aboutvarious procedures not having the prototypes it expects, in particularmemset, memcpy, and memcmp. It's not obvious from the warning messagesyou get exactly what prototype gcc is expecting.

In general there's no particular reason why a function named `memcpy' inthe kernel should have the same prototype (or even the same behaviour) asa function named `memcpy' in a userland program, which is why we use-fno-builtin.